You can't refuse legal tender as payment for a debt, regardless of the terms of your contract, and then expect the court system to enforce your contract.
You don't have to accept legal tender for a sale, but once a debt exists you'll only get to use the government's enforcement powers if you don't refuse legal tender.
Thanks, that's what I thought but I wanted to make sure. In other words, contracts involving bitcoins are not enforceable in courts.
I'm wondering though, could you sue for breach of contract or something along those lines? And, in my first example, if you did accept $s but insisted on getting the going exchange rate for bitcoins (lets say 100 bitcoins at $11/each, $1100) would you expect the courts to rule in your favor in that full amount?